Bitflow
Bounty Range
$1,000 - $100,000
external program
Bitflow
[/bug-bounty/](Back to Explore)
Bitflow, a decentralized exchange (DEX) built on the Stacks blockchain, positioning itself as a key liquidity hub for Bitcoin DeFi users (traders, liquidity providers, and developers).
Stacks Exchange Defi DEX Liquid Staking Clarity NextJS
Maximum Bounty $100,000 Live Since 26 November 2025 Last Updated 08 December 2025
PoC Required
Vault program
Arbitration enabled
[https://bugs.immunefi.com/dashboard/new-submission?utm_source=immunefi](Submit a Bug)
/bug-bounty/ /bug-bounty/bitflow/information/#top/bug-bounty/bitflow/scope/#top/bug-bounty/bitflow/resources/#top
Funds available
$2,923.01
30d Avg. Funds availability
$2,864.61
Assets in vault
Public vault address
0x7d0a13a66e72A8A9268bb93d2e81664509209c08 https://etherscan.io/address/0x7d0a13a66e72A8A9268bb93d2e81664509209c08?utm_source=immunefi
Bitflow provides rewards in USDC on Ethereum, denominated in USD.
Smart Contract Critical Max: $100,000Min: $20,000
Primacy of Impact
High Max: $20,000Min: $2,500
Primacy of Impact
Medium Flat: $2,000 Primacy of Impact
Low Flat: $1,000 Primacy of Impact
Critical Reward Calculation
Reward amount is 10% of the funds directly affected up to a maximum of:
$100,000 Minimum reward to discourage security researchers from withholding a bug report:
$20,000
Websites and Applications Critical Max: $25,000Min: $5,000
Primacy of Impact
Critical Reward Calculation All other impacts that are classified as Critical will be rewarded a flat amount of:
$5,000 The rest of the severity levels are paid out according to the Impact in Scope table.
Rewards Body
Reward Calculation for Critical Level Reports
For critical smart contract bugs, the reward amount is 10% of the funds directly affected up to a maximum of USD 100 000. The calculation of the amount of funds at risk is based on the time and date the bug report is submitted. However, a minimum reward of USD 20 000 is to be rewarded in order to incentivize security researchers against withholding a critical bug report.
Repeatable Attack Limitations
If the smart contract where the vulnerability exists can be upgraded or paused, only the initial attack will be considered for a reward.
The amount of funds at risk will be calculated with the impact of the first attack being at 100% and then a reduction of 25% from the amount of the first attack for every [720 blocks] the attack needs for subsequent attacks from the first attack, rounded down.
Reward Calculation for High Level Reports
High impacts concerning theft/permanent freezing of unclaimed yield/royalties are rewarded within a range of USD 2 500 to USD 20 000 with the reward calculated based on 100% of the funds at risk, though capped at the maximum high.
In the event of temporary freezing, the reward doubles from the full frozen value for every additional [24h] that the funds are temporarily frozen, up until a max cap of the high reward.
For critical web/apps bug reports will be rewarded with USD 25 000, only if the impact leads to:
A loss of funds involving an attack that does not require any user action
Private key or private key generation leakage leading to unauthorized access to user funds
All other impacts that would be classified as Critical would be rewarded a flat amount of USD 5 000. The rest of the severity levels are paid out according to the Impact in Scope table.
The SIP10 implementation of STX we deployed for use across legacy DEXs and soon with the HODLMM (SM1793C4R5PZ4NS4VQ4WMP7SKKYVH8JZEWSZ9HCCR.token-stx-v-1-2) is within scope, and all other fungible tokens are not in scope. Other contracts deployed by SM1793C4R5PZ4NS4VQ4WMP7SKKYVH8JZEWSZ9HCCR or SPQC38PW542EQJ5M11CR25P7BS1CA6QT4TBXGB3M are not in scope.
Reward Payment Terms
Payouts are handled by the Bitflow team directly and are denominated in USD. However, payments are done in USDC on Ethereum.
The calculation of the net amount rewarded is based on the average price between CoinMarketCap.com and CoinGecko.com at the time the bug report was submitted. No adjustments are made based on liquidity availability.
[/bug-bounty/bitflow/scope/#impacts]( View impacts in scope)
Bitflow, a decentralized exchange (DEX) built on the Stacks blockchain, positioning itself as a key liquidity hub for Bitcoin DeFi users (traders, liquidity providers, and developers). Bitflow has a history of recreating battle tested DEX smart contracts in the Clarity smart contract language, as well as innovating with new designs such as the variable midpoint stableswap. In the past, Bitflow has delivered Curve style pools, Uniswap V2 style pools, and Jupiter style aggregator contracts for multi-dex swaps.
This BBP (bug bounty program) however will initially focus exclusively on a new orderbook style AMM that unlocks concentrated liquidity in the Stacks ecosystem. Bitflow calls this the HODLMM – High-throughput, Orderbook-style, Decentralized Liquidity Market Maker. Concentrated liquidity is much more efficient for traders and liquidity providers compared to legacy AMMs like the Uniswap V2 design, and this implementation draws inspiration from Trader Joe’s Liquidity Book AMM and Meteora’s DLMM designs. Over time, the scope may expand to include contracts for legacy AMMs and more peripheral contracts built on HODLMM
For more information about Bitflow, please visit https://www.bitflow.finance/?utm_source=immunefi
Bitflow provides rewards in STX on Stacks, denominated in USD. For more details about the payment process, please view the Rewards by Threat Level section further below.
Primacy of Impact vs Primacy of Rules
Bitflow adheres to the Primacy of Impact for the following impacts:
Smart Contract - Critical
Smart Contract - High
Web/App - Critical
Primacy of Impact means that the impact is prioritized rather than a specific asset. This encourages security researchers to report on all bugs with an in-scope impact, even if the affected assets are not in scope. For more information, please see [https://immunefisupport.zendesk.com/hc/en-us/articles/12340245635089-Best-Practices-Primacy-of-Impact?utm_source=immunefi](Best Practices: Primacy of Impact )
When submitting a report on Immunefi’s dashboard, the security researcher should select the Primacy of Impact asset placeholder. If the team behind this project has multiple programs, those other programs are not covered under Primacy of Impact for this program. Instead, check if those other projects have a bug bounty program on Immunefi.
If the project has any testnet and/or mock files, those will not be covered under Primacy of Impact.
All other impacts are considered under the Primacy of Rules, which means that they are bound by the terms and conditions set within this program.
Proof of Concept (PoC) Requirements
A PoC, demonstrating the bug's impact, is required for this program and has to comply with the[https://immunefisupport.zendesk.com/hc/en-us/articles/9946217628561-Proof-of-Concept-PoC-Guidelines-and-Rules?utm_source=immunefi]( Immunefi PoC Guidelines and Rules.)
Public Disclosure of Known Issues
Bug reports covering previously-discovered bugs (listed below) are not eligible for a reward within this program. This includes known issues that the project is aware of but has consciously decided not to “fix”, necessary code changes, or any implemented operational mitigating procedures that can lessen potential risk.
Bitflow HODLMM Known Issues (Most here were acknowledged during Completed Audits)
Pool Operations Lack Deadline Checks
Deadlines allow users to specify the time by which the operation must be executed otherwise it would be invalid.
Pool verification status set during pool creation, and allows unverified pools to exist
Even though they can’t be verified, in theory malicious pools contracts can still be deployed and swapped through via core. This is intentional to ensure that permissionless pool creation is possible when public pool creation is enabled. Note that liquidity remains isolated in each pool contract.
Verified pools can still contain malicious tokens
Malicious tokens can therefore be swapped through core or peripheral routers
At scale, there is no way to check on-chain for whether or not a token is malicious during pool creation (unlike template pool contracts that can be compared to a hash of the code body).
Peripheral router contracts could be built on top to maintain a list of verified tokens (separate from core) to add more protection to user’s swaps and liquidity provision.
Avoid using ‘tx-sender’ for Caller Authorization
Throughout the codebase there are instances where tx-sender is used instead of contract-caller or passing the caller address. By doing this, users that fall to phishing scams and interact with malicious contracts can unwittingly interact with the codebase and execute sensitive operations. By using contract-caller, we lose composability for more peripheral contracts to be built on top; tx-sender allows for that which means that phishing is possible. Users looking out for post conditions will also help mitigate risk of phishing attacks.
Variable Fee Design Choices
The current variable fee is intended to serve as a volatility fee, where many bin changes in recent blocks will result in increased variable fee, which can also be reset or reduced.
The pool uses specific data points to calculate the fee. Admins can calculate off-chain the fee and set the fees via a set-variable-fees call, with the intent that in the future, a peripheral contract will update these via asynchronous calls.
With this design, multi-bin swaps can often precede a fee adjustment
Lower fee swaps can be frontrun if users see a fee-increase transaction in the mempool.
Users may be charged more than needed if the transactions to reset or lower the variable fees do not get confirmed before more swaps get confirmed
Users could be charged too high of a variable fee by a malicious admin that also deploys liquidity into a bin
Absence of Preview Functions for Key Operations
Current implementation does not offer any mechanism of previewing operation results.
Intention is to create a peripheral contract with preview functions, one for each major operation in the core contract: swap-x-for-y, swap-y-for-x, add-liquidity, withdraw-liquidity, and move-liquidity
Remove Redundant begin Blocks
Throughout the codebase, after let declarations, the implementation redundantly adds a begin block instead of just writing the next statements as it is normally allowed by the let block. This is done, redundantly in almost all contracts, all instances of begin code blocks can be removed.
Bin steps can be added with wrong values and they cannot be updated/removed
With the ability to migrate to new core contracts, admins can upgrade with the corrected bin factors.
Multi-bin swaps using favorable bins can actually lead to worse outcomes
A user can actually do worse when favorable bins are available because the capacity of those bins is not as high as they expected. The result is unexpected funds loss for the user. However, the user can prevent this by setting min-received correctly for each swap step. The unfavorable bin logic only compares the active bin ID to the expected bin ID, not bin balances or other factors. Bitflow calculates min-received per swap off-chain and enforces it on-chain. Thus, this was assessed by auditors as informational.
Malicious core contract upgradability if an admin is compromised
A malicious admin could attempt to upgrade pools to use a new core contract
if original deployer or admin hasn’t frozen migration and hasn’t noticed within the cooldown period of at least 1 week.
In a previous design, Bitflow had no way to upgrade the core contract. The likelihood of needing to roll out a new version is eventually high.
Implement Timelocks for Sensitive Configuration Changes
Previous Audits
Bitflow’s completed audit reports can be found at https://docs.bitflow.finance/Bitflow-documentation/resources/audits?utm_source=immunefi. Any unfixed vulnerabilities mentioned in these reports are not eligible for a reward.
No KYC information is required for payout processing.
Proof of concept is always required for all severities.
Category 3: Approval Required
Default prohibited activities
Any testing on mainnet or public testnet deployed code; all testing should be done on local-forks of either public testnet or mainnet
Any testing with pricing oracles or third-party smart contracts
Attempting phishing or other social engineering attacks against our employees and/or customers
Any testing with third-party systems and applications (e.g. browser extensions) as well as websites (e.g. SSO providers, advertising networks)
Any denial of service attacks that are executed against project assets
Automated testing of services that generates significant amounts of traffic
Public disclosure of an unpatched vulnerability in an embargoed bounty
[https://immunefi.com/rules/](Any other actions prohibited by the Immunefi Rules)
The project may be receiving reports that are valid (the bug and attack vector are real) and cite assets and impacts that are in scope, but there may be obstacles or barriers to executing the attack in the real world. In other words, there is a question about how feasible the attack really is. Conversely, there may also be mitigation measures that projects can take to prevent the impact of the bug, which are not feasible or would require unconventional action and hence, should not be used as reasons for downgrading a bug's severity.
Therefore, Immunefi has developed a set of feasibility limitation standards which by default states what security researchers, as well as projects, can or cannot cite when reviewing a bug report.
[https://immunefisupport.zendesk.com/hc/en-us/articles/19430444320401-Pre-Impact-Bug-Monitoring?utm_source=immunefi](Pre-Impact Bug Monitoring)
[https://immunefisupport.zendesk.com/hc/en-us/articles/17243068885265-Attack-Investment-Amount?utm_source=immunefi](Attack Investment Amount)
[https://immunefisupport.zendesk.com/hc/en-us/articles/17454897136401-Attacks-With-A-Financial-Risk-To-The-Attacker?utm_source=immunefi](Attacks With A Financial Risk To The Attacker)
[https://immunefisupport.zendesk.com/hc/en-us/articles/17455102268305-When-Is-An-Impactful-Attack-Downgraded-To-Griefing?utm_source=immunefi](When Is An Impactful Attack Downgraded To Griefing?)
[https://bugs.immunefi.com/dashboard/new-submission?utm_source=immunefi](Submit a Bug) 30d Avg. Funds Availability$2,864.61
[/bug-bounty/bitflow/scope/#assets](Total Assets in Scope11 )